SU1401394A1 - Device for measuring electric power - Google Patents

Abstract

This invention relates to a digital electrical measuring technique. The device contains sensors 1 and 2 of voltage and current, block 3 multiplying analog signals, block 4 of determining the sign, integrators 5 and 6, analog-digital converters 11-14, calculator 15, block 16 of indication, block 17 of interface and control 18 . Introduction of an analog signal squaring unit 7, switch 8, integrators, tori 9 and 10 expands the functionality, improves the measurement accuracy of generating and consuming exchange and reactive energy in a generator-consumer system at various intensities of electromagnetic energy conversion in the consumer and other types energy during the period of work. 1 il.

Description

The invention relates to a digital electrical measuring technique and can be used in evaluating the supply of electricity in electrical and energy circuits to increase the efficiency of distribution and transmission of electrical energy from generators to consumers.

The purpose of the invention is to expand the functionality, improve the accuracy of measuring the generation and consumption of exchange and reactive energy in a generator-consumer system at different intensities of converting electromagnetic energy in a consumer to other forms of energy over a period of operation.

The drawing shows a block diagram of a device for measuring electrical power.

The device contains a voltage sensor 1, a current sensor 2, an analog signal multiplying unit 3, a sign determining unit 4, first and second integrators 5 and 6, an analog signal squaring unit 7, a switch 8, a third and fourth integrators 9 and 10, analog -Digital converters 11-14, calculator 15, display unit 16, interface block 17 and control panel 18, the outputs of sensors 1 and 2 of voltage and current are connected to the inputs of block 3 multiplying analog signals, the output of which is connected to the input of block 4 mark, the outputs of which podkl Points to the inputs of the first and second integrators 5 and 6, the inputs of the third and fourth integrators 9 and 10 are connected to the outputs of the switch 8, the first input of which is connected through the block 7 of raising analog signals to the square to the output of the current sensor 2. and the other two are connected to the outputs The sign definition unit 4, the outputs of the integrators 5, 6, 9 and 10 are connected via digital converters 11-14 to the inputs of the calculator 15, the first to fourth control outputs of which are connected to the control inputs of the integrators 5, 6, 9 and 10, the calculator 15 is connected bidirectionally bus with display unit 16, interface block 17 and control panel 18.

A device for measuring electrical power works as follows.

Sensors 1 and 2 of voltage and current carry out galvanic isolation, matching the signal levels of the energy circuits and the measuring part of the device, and also instantaneous values of the voltage Unxjt) and current 1 in (1) are continuously measured. The output voltage of the voltage sensor 1 UBbixi (t) is proportional to the measured voltage (Vyh (t) auUBx (t)), and the sensor 2 of the current UBbix2 (t) is proportional to the measured current (UBbix2 (t) o (:; iBx (t)), is fed to the block 3 multiplying analog signals, the output of which produces a signal proportional to the instantaneous power

five

0

five

0

five

0

P (t) a "UBx (t) aiiBx (t),

where ac, and / are the coefficients of proportionality.

The output signal of the analog signal multiplying unit 3 is supplied to the character determining unit 4, which allows the output signals to be divided by the sign. The positive component of the signal from the output of the sign determining unit 4 is fed to the integrator 5, integrating the instantaneous power (t) (P (t) p (t) -0). The negative component of the signal from the output of the sign determining unit 4 is fed to the integrator 6, which integrates the instantaneous power P (t) {p (t) p (t) 0).

The signal from the output of current sensor 2 is also fed to the input of a signal squaring unit 7, at the output of which a signal is formed that is proportional to the value of ilx (t). The output voltage of the signal squaring unit 7 is supplied to the switch 8, which, depending on the value of the control signals from the output of the sign definition unit 4, supplies these voltages to one of the inputs of the integrators 9 and 10 (if p (t) O, then the output the signal of block 7 is fed to the input of integrator 9; if p (t) O, then the output signal of block 7 is fed to the input of integrator 10). At the outputs of the integrators 9 and 10, signals are generated that are proportional to the values

(i) di; D) ui,

where t is the time interval at p (t) 0; i is the time interval at p (1) 0.

Information in analog form from integrators 5, 6, 9, and 10 is supplied through analog-digital converters 11-14 to calculator 15, which calculates active, exchange, and reactive power using the formulas

R

- p + + p (p + + p-) 1+

45

О - „(D + -.) 1 ° - V | -Ь I

50

as well as exchange Woc and reactive Wp energy according to

W

,, y + (W + + W-) I + W1-1- -1-155

W - GSH + (W + + W-) +

Wp - n (W j-t- | J--

where (t) i (t) dt;

W- Su (t) i (t) dt; D + -; p- -. OTT

The output signals of calculator 15 are active power p, exchange Qo6 and reactive Qp power, as well as active WA, exchange Wo6 and reactive WP energy.

The display unit 16 displays the output signals P, Qo6, Qp, WA, Wo6, Wp.

In order to interface the device with standard interfaces of the measuring systems, an interface block 17 is included in the measurement device. The control panel 18 is used to control the operation of the entire device.

Claims (1)

Invention Formula An apparatus for measuring electrical power, comprising sensors for example current and output, the outputs of which are connected to the inputs of the multiplier analog signals, the output of which is connected to the input of the sign determining unit, two integrators whose inputs are connected to the outputs of the sign determining unit, four analog-to-digital converters, the inputs of the first and second of which are connected to the outputs first and second integrators, and you The analog-to-digital converter drives are connected to the inputs of the calculator, which is connected by a bi-directional bus to the display unit, the interface unit and the control panel, and the first and second outputs of the calculator are connected to the control inputs of the first and second integrators, in order to extend the functionality , improving the accuracy of measuring the generation and consumption of exchange and reactive energy in a generator-consumer system at different intensities of the conversion of electromagnetic energy into a consumer in other types of energy over a period of operation, a squared signalization unit, a third and fourth integrator switchboard are entered into it, the input of the squared signalization unit is connected to the current sensor output, and the output is connected to the first input of the switchboard, two other inputs which are connected to the outputs of the sign determining unit, the switch outputs are connected to the inputs of the third and fourth integrators, the outputs of which are connected to the inputs of the third and fourth analog-to-digital converters, and the control inputs Integrator s are connected to the third and fourth outputs of the calculator.